Conventionally, absorbent articles such as open-type diapers have a vertically long shape extending from the front waistline (ventral portion) to the back waistline (back portion) of a wearer. In general, such absorbent articles include a front waistline portion to be fitted to the front waistline of a wearer, a back waistline portion to be fitted to the back waistline of the wearer, and a crotch portion to be fitted to the crotch of the wearer, the crotch portion arranged between the front waistline portion and the back waistline portion.
The absorbent article also includes side flaps (flap portions) which are used to temporarily attach one of the front waistline portion and the back waistline portion to the other, so that the wearer can easily wear the absorbent article. The side flaps outwardly extend in the width direction of the absorbent article, and is arranged from one of the waistline portions to the other when the wearer wears the absorbent article.
In general, while a strip-shaped front waistline web to be formed into the front waistline portion and a strip-shaped back waistline web to be formed into the back waistline portion are being conveyed in parallel, the side flaps are arranged on one of the front waistline web and the back waistline web alternately at predetermined intervals by a flap transferring mechanism (see, for example, Patent Literature 1).
Moreover, while the front waistline web and the back waistline web are being conveyed in parallel, multiple crotch portion transferring mechanisms arrange the crotch portions at predetermined intervals between the front waistline web and the back waistline web, so that the crotch portions are up side down alternately on the front waistline web and the back waistline web (see, for example, Patent Literature 1).